Integrated circuits (ICs) continue to become more advanced and require more functional elements. As such the geometries of these functional elements become smaller and deviations within the manufacturing process become much more critical. These deviations may degrade performance criteria and more importantly reliability. Performance criteria can normally be measured during wafer and device test. However, reliability may be much more difficult to determine. Specifically, dimensions of functional elements are reduced to the limits of the manufacturing process. As such, some ICs may have functional element dimensions too small for adequate reliability, while performance criteria of these devices may not degrade but even be enhanced. Microscopy methods for screening can be used to inspect dimensions. However, with processes less than 100 nanometers, a scanning electron microscope (SEM) can required. This technique is not practical on a per IC device basis in the manufacturing process.
Therefore, there is a need for techniques and test structures to ensure reliability of ICs at both a wafer level and a device level during the manufacturing process.